1. Field of the Invention
This invention relates to the generation of mechanical or electrical power from the fluid dynamic energy of a fluid transported through a flowline or a pipeline and, more particularly, relates to the selective generation of electrical power at remote locations on a flowline or pipeline used to transport fluids without substantially changing the downstream fluid pressure in the flowline.
2. Description of the Prior Art
Electrical power is acquired for many operations performed in conjunction with the production, gathering, and distribution of fluids and various flow media in the petroleum industry. For example, multi-well gathering facilities require electrical power for heater/treater control panel, separator control panels, tank and flowline heaters, fire protection asistance, gas detector systems, electrohydraulic pumps, chemical injection pumps, telemetry equipment, and microprocessor-based control systems. Electrical power is also necessary on remote wells such as carbon dioxide producing and injection wells, gas injection wells, and water flood sites. Electrical power is necessary for actuating adjustable flowline chokes, power and flowline heaters, safety systems, and microprocessor-based telemetry equipment. Electrical power is necessary on pipelines, near pipeline valves for power in control systems for valve operators, line break systems, electrohydraulic power packs, and telemetry equipment. In offshore applications, electrical power is necessary for navigation systems such as fog horns, navigation lights, and communication systems. In short, there are a number of remote locations where continuous electrical power or intermittent electrical power is required for performing operations in the petroleum industry. In many of these locations it is uneconomical to employ engine-driven generators. Solar array panels have been employed to provide electrical power in remote locations. In offshore applications, marine cable has been laid to provide electrical power at remote locations.
Various prior devices have been used in an attempt to generate electrical power from the fluid dynamic energy of a working fluid flowing through a line or pipeline in the petroleum industry. These systems have commonly employed impellers or turbine rotors mounted in the flowline with the axis extending either parallel to or coincident with the axis of the flowline, to generate sufficient shaft horsepower to drive a conventional electrical generator. For example, shaft-driven brush commutated DC permanent magnet generators driven by coaxial mud turbines have been employed downhole in a pipe string to power well logging and other equipment.
In addition to conventional axial flow turbines, shaft horsepower has also been developed in other applications by use of impulse turbines powered by fluids engaging the turbines at their periphery. Impulse turbines driven by a series of nozzles located on the periphery of a chamber containing the turbine are disclosed in U.S. Pat. Nos. 4,060,336 and 4,150,918.
No prior art method or apparatus using a turbine-driven generator to convert the fluid dynamic energy of a working fluid in a flowline into electrical power is known in which the turbine-driven generator may be attached or removed while the fluid is flowing through the line and without substantially changing the downstream fluid pressure as a consequence of such attachment or removal. Furthermore, no prior device provides for a selective fluid bypass capable of bypassing fluids around the turbine when electrical power is not required, and also permitting selective actuation of the turbine as desired without substantially affecting the downstream fluid pressure.